Components such as, for example, turbine blades or vanes of a gas turbine have cooling-air bores. Cooling-air bores of this type are made directly in the substrate before the further application of layers during the production of new components, or are already present in a component to be refurbished, in the case of which the coatings are replaced. Both cases are subject to the problem of “coat down”, i.e. the coating material penetrates into the cooling-air bores and undesirably closes them.
There are processes for closing the cooling-air bores where complete coverage, in particular also during the coating process, is not always ensured.
The subsequent removal of the “coat down” from the cooling-air bores is subject to the problem of correct alignment of the cooling-air row in the apparatus by means of which the coating is removed from the cooling-air bores, since the alignment differs from a desired geometry.